Adds the option to enable delay loading of CUDA DLLs on Windows. This is particularly useful to use the same binary on systems with and without CUDA support without distributing the CUDA DLLs to systems that cannot use them at all due to missing CUDA-supported hardware.
Resolves#13509
Currently, the LOADER_DIR is set as os.path.dirname(os.path.abspath(__file__)). This does not point to the true library path if the cv2 folder is symlinked into the Python package directory such that importing cv2 under Python fails. The proposed change only resolves symbolic links correctly by calling os.path.realpath(__file__) first and does not change anything if __file__ contains no symbolic link.